#Requires -Version 7
<#
.SYNOPSIS
    Provision a Python venv and launch the pymodbus DL205 simulator.

.DESCRIPTION
    Idempotent: re-runs skip venv provisioning when tests/sim/.venv is fully provisioned.
    Spawns 'pymodbus.simulator' with the DL205/DL260 register profile on a configurable
    port; the server process stays attached so Ctrl-C (or parent exit) kills it cleanly.

    pymodbus version pin: 3.13.0
    (Matches the profile comment in DL260/dl205.json. Record the version here AND in
    tests/sim/README.md so it is never lost across re-provisioning.)

    API note: pymodbus 3.13.0 uses 'pymodbus.simulator' (not the legacy 'pymodbus.server
    run' command). The Modbus TCP port is set in the JSON config; this script writes a
    temp config that overrides the port so the free-port-picker pattern works.
    aiohttp is required by the pymodbus simulator HTTP console and is installed alongside
    pymodbus.

.PARAMETER Profile
    Path to the pymodbus JSON profile. Defaults to ../../DL260/dl205.json relative to
    this script's directory (i.e. the checked-in DL205 quirk profile).

.PARAMETER Port
    TCP port for the Modbus server to listen on. Defaults to 5020.

.EXIT CODES
    0  Clean exit (Ctrl-C or natural termination).
    1  Python not found, or venv provisioning failed.
    2  pymodbus.simulator launch failed.
    3  Profile file not found.
#>
[CmdletBinding()]
param(
    [string]$Profile = (Join-Path $PSScriptRoot '..\..\DL260\dl205.json'),
    [int]$Port = 5020
)

Set-StrictMode -Version Latest
$ErrorActionPreference = 'Stop'

# ── 1. Resolve and validate the profile path ─────────────────────────────────
$ProfileResolved = (Resolve-Path -Path $Profile -ErrorAction SilentlyContinue)?.Path
if (-not $ProfileResolved) {
    Write-Error "Profile not found: $Profile"
    exit 3
}

# ── 2. Locate Python ─────────────────────────────────────────────────────────
# Try 'python' first (standard PATH install), then the Windows-store launcher 'py'.
$pythonExe = $null
foreach ($candidate in 'python', 'py') {
    try {
        $ver = & $candidate --version 2>&1
        if ($LASTEXITCODE -eq 0) {
            $pythonExe = $candidate
            Write-Host "[sim] Python found via '$candidate': $ver"
            break
        }
    } catch {
        # not on PATH — continue
    }
}
if (-not $pythonExe) {
    Write-Error @"
Python 3.10+ is required to run the DL205 simulator but was not found on PATH.
Install Python from https://www.python.org/downloads/ and ensure it is on your PATH,
or use the Windows Store launcher ('py').
"@
    exit 1
}

# ── 3. Provision the venv (idempotent) ───────────────────────────────────────
# pymodbus version pin: 3.13.0
# Update this constant AND tests/sim/README.md together if you re-pin.
$PYMODBUS_VERSION = '3.13.0'

$venvDir        = Join-Path $PSScriptRoot '.venv'
$venvPython     = Join-Path $venvDir 'Scripts\python.exe'
$pipExe         = Join-Path $venvDir 'Scripts\pip.exe'
$simulatorExe   = Join-Path $venvDir 'Scripts\pymodbus.simulator.exe'  # sentinel for complete install

# Provisioning is idempotent: we only skip it when pymodbus.simulator.exe exists.
# Checking only the .venv directory is not enough — a previous run killed mid-install
# leaves the directory but without pymodbus installed.
$needsProvision = (-not (Test-Path $simulatorExe))

if ($needsProvision) {
    if (-not (Test-Path $venvDir)) {
        Write-Host "[sim] Creating venv at $venvDir ..."
        & $pythonExe -m venv $venvDir
        if ($LASTEXITCODE -ne 0) {
            Write-Error "Failed to create Python venv (exit $LASTEXITCODE)."
            exit 1
        }
    } else {
        Write-Host "[sim] Venv exists but pymodbus is not fully installed — installing now."
    }

    # pymodbus 3.13.0 does not provide a [server] extra; the simulator module is
    # included in the base package.  aiohttp is required by the simulator's HTTP
    # console and is not a declared dependency of pymodbus, so we install it
    # explicitly here.
    Write-Host "[sim] Installing pymodbus==$PYMODBUS_VERSION + aiohttp ..."
    & $pipExe install "pymodbus==$PYMODBUS_VERSION" aiohttp
    if ($LASTEXITCODE -ne 0) {
        Write-Error "Failed to install pymodbus / aiohttp (exit $LASTEXITCODE). Check network or proxy settings."
        exit 1
    }

    Write-Host "[sim] Venv provisioned."
} else {
    Write-Host "[sim] Venv and pymodbus already provisioned — skipping."
}

# ── 4. Prepare a port-specific config file ───────────────────────────────────
# pymodbus.simulator 3.13.0 reads the Modbus TCP port from the JSON config, not
# from a command-line --port flag.  To allow the fixture's free-port-picker pattern,
# we write a temp config that is a copy of the base profile but with srv.port
# overridden to $Port.
$tempConfig = [System.IO.Path]::GetTempFileName() + '.json'
try {
    $json = Get-Content -Raw $ProfileResolved | ConvertFrom-Json -Depth 20
    $json.server_list.srv.port = $Port
    $json | ConvertTo-Json -Depth 20 | Set-Content -Encoding UTF8 $tempConfig
    Write-Host "[sim] Wrote temp config with port=$Port to: $tempConfig"
}
catch {
    Write-Error "Failed to prepare port-specific config: $_"
    exit 2
}

# ── 5. Launch pymodbus simulator ─────────────────────────────────────────────
# pymodbus 3.13.0 API: pymodbus.simulator --json_file <path> --modbus_server <key>
#   --modbus_device <key>
# We don't pass --http_port because we don't need the REST API in tests.
# The process is kept alive in the foreground; Ctrl-C (or parent-exit Kill) stops it.
Write-Host "[sim] Starting pymodbus DL205 simulator on Modbus TCP port $Port ..."

try {
    & $simulatorExe `
        --json_file $tempConfig `
        --modbus_server srv `
        --modbus_device dev
    $exitCode = $LASTEXITCODE
} catch {
    Write-Error "Failed to launch pymodbus.simulator: $_"
    Remove-Item -Force $tempConfig -ErrorAction SilentlyContinue
    exit 2
} finally {
    Remove-Item -Force $tempConfig -ErrorAction SilentlyContinue
}

# A non-zero exit from pymodbus is unexpected (0 = clean shutdown).
if ($exitCode -ne 0) {
    Write-Error "pymodbus.simulator exited with code $exitCode."
    exit 2
}

exit 0